Electric motor control



Nov. 22, 1938.

R. '-G. LOCKETT 2,137,534

ELECTRIC MOTOR CONTROL Filed May 3, 1937 W WM 26 I @(Xmmg,

Patented Nov. 22, 1938 I "PATENT OFFICE 2,137,534 ELECTRIC MOTOR.CONTROL Ralph G. Lockett, Wauwatosa, Wis., asslgnor to Cutler-Hammer,Inc., Milwaukee, Wis., a corporation of Delaware application May a,museum No. 140,362

14 Claims.

This invention relates to improvements in electric motor control. Theinvention relates more particularly to a control system for a reversibleelectric motor driving a rotatable load, such as the cylindricalcontainers used in laundry machines for clothes washing and/or drying,and in machines for dyeing operations.

Machines of the character aforementioned are operated in regular cycles,which may con-- sist in rotating the cylindrical container alternatelyin opposite directions for predetermined periods of time or for apredetermined number of revolutions, with intermediate periods whereinthe cylinder coasts at diminishing speed or 15 to rest before beingdriven in the opposite direction, or is gradually slowed or brought torest by the driving motor through plugging or dynamic braking of thelatter. These machines are ordinarily operated with varying loads in thecy1- inder, the cylinder being rotated in a tubor casing which may ormay not contain liquid. The foregoing condtions aiiect the inertia ofthe various moving parts of the machine and consequently vary the timerequired for these parts to come to rest.

It is important to be able to effect control of the driving motor formachines of the aforementioned character in a manner which will reversethe direction of operation of the cylinder as soon as it has come torest either by coasting or plugging; the reversal being eifected in amanner which is not toopronounced -so as to smoothly take up the backlash in the driving connections and avoid destructive pounding and wearand possible breakage of the latter. It is also important to effectsmooth reversal and acceleration of the cylinder to avoid Wedding andtangling of the clothes, goods, or other load therein. Various deviceshave heretofore been proposed in an attempt to approach in some degreethe aforementioned desirable features of control. Many of these devices,as for example, various well known pilot motor operated switchingdevices, involve complicated and expensive equipment.

An object of the invention is to provide novel, control means foraccomplishing the aforementioned desirable results. 7 50 Another objectis to provide means of the aforementioned character which is simple,eflicient and inexpensive.

Anotherobject is to provide a control system of the aforementionedcharacter having the desired features of manual and automa.tlc control,

Other objects and advantages of the invention will hereinafter appear.

Theaccompanying drawing illustrates schematically and diagrammaticallyan embodiment of the invention which will now be described,it beingunderstood that the embodiment illustrated is susceptible ofmodification as to certain details thereof without departing from thescope of the appended claims.

I have illustrated my invention as applied to 10 I the control of areversible electric motor driving, a cylindrical container which isrotatable upon a horizontal axis,-such as is used in the laundryindustry. In a device of this character it is desired to rotate thecylinder a predeter- 15 mined equal number of times in each direction,this being particularly desirable in the operation of machines used fordyeing operations,

between reversals of the cylinder unsuitable, 30

since the occurrence of. full power reversal of the cylinder at a momentbefore or after that in which the cylinder attains zero speed results inshock and undue wear upon the machine.

I propose to attain the aforementioned desirable objects by employing atraveling nut double-throw limit switch operated by the rotatablecylinder itself. This provides for alternate rotation of the cylinder apredetermined equal number of times in each direction. Operation 40 ofthe limit switch effects interruption, respectively, of the energizingcircuits of the active reversing switch and an accelerating switch, and.effects establishment of the-energizing circuit for the other reversingswitch. The latter provides 4.5 for plugging the motor under reducedvoltage and torqueconditions; The back lash in the driving connectionsis thus taken up gradually, the cylinder is smoothly and graduallybrought to zero speed and immediately started slowly o in the oppositedirection. Immediately upon. reversal of the driving motor and thecylinder the accelerating" switch is brought in, for which purpose Iprovide a switch which is responsive to the direction of operation ofthe equipment.

This switch may be arranged for operation either directly by the motoror by the cylinder,and while I prefer to employ a friction belt orslipclutch operating connection for the switch, it will be apparent tothose skilled in the art that any of thewell known pneumatic, hydraulicor magnetic-drag devices may be employed.

More -specifically,refern'ng to the drawing, the numeral I designatesacylinder or drum 1 which is rotatable, preferably upon a horizon- .talaxis, within a stationary casing or tub 2 as by means of a reversibleelectric motor 3. Motor 3 may be of standard squirrel cage type, andsuitable speed-reducing gearing 4 is preferably interposed between themotor shaft and the shaft of cylinder I. Tub 2 is provided with anopening, the door or closure for which is shown schematically at 5, toprovide for access to cylinder 2 for loading and unloading thereofthrough a suitable opening or openings provided in the latter. Motor 3is adapted to be supplied with current from a suitable source of supply,represented by lines L L and L through the medium of a pair ofelectromagnetically oper- 25 able reversing switches 6 and I. Theoperating windings 6 and I'- of switches 6 and 1 are respectivelysubjected to control in part by the limit switches 8 and 9,--the latterbeing mechanically connected, as by means of the pivoted link III, toinsure joint operation thereof.

The shaft of cylinder l is provided with a threaded extension II whichis adapted to cooperatively engage a pair of traveling nuts I2 and I 3,aguide rod or plate It being adapted to restrain said nuts againstrotation. The arrangement is such that upon a predtermined number ofrevolutions of cylinder I in one 'direcis initially rendered eifectivefor completing an energizing circuit for the winding 6 or I respectivelyassociated therewith upon closure of the push button switch I6.Energization of the winding 5 or l is further dependent on switch I1 andinch push button switches I8 and I9.

Switch I1 is adapted to be operated by the door 5 of tub 2, said switchhaving up contacts I1 which are adapted to be closed when door 5 isclosed, and down contacts I I which are adapted to be closed when ,door5 is open. Inch push button switches I8, and I9 are respectivelyprovided with normally closed up-contacts I8 and I9 and normally opendown contacts I8 and I9 The system further includes an accelerating by africtionally operated switch 2I. The equipment is preferably providedwith -an electromagnetically releasable brake. 22 shown here inassociation with the shaft of motor 3,

Thus with the several parts in the positions thereof illustrated, theequipment may be started by closing the push button switch I6. Thiscompletes an energizing circuit for the winding I of reversing switch I,said circuit extending from line L through push button switch I6,contacts switch 20, the winding 2|I of which is controlled I I of doorswitch II, contacts l3 and I3, re spectively, of inch push buttonswitches I3 and I9, by conductor 23 through limit switch 9, byconductors 24 and 25, through said winding 1*, by conductor 30 throughthe normally closed contacts 20 of accelerating switch 20, and byconductor 3| to line L Contacts l 1, 1 are thus closed to establishpower connections through resistances R R and R, respectively, foroperation of motor 3 and cylinder I at a rela-- tively slow speed in adirection such as to cause movement of nuts I2 and I3 toward the right.

, Normally open contacts 1 and I of switch 'I are also closed, contactsI providing a maintaining circuit for winding 1* paralleling theinterlock contacts 20, and contacts 1 providing an electrical interlockfor winding 20* of accelerating switch 20.

It is preferred that the resistances R. R, R be of a relatively highvalue, so that the torque of motor 3 with the resistances in circuit islimited to a pointwhich is just sufiicient to break the cylinder shaftloose in its bearing on the initial start.

In accordance with my invention there is provided the switch2I,'previously referred to, comprising an oscillatable contactor 32 anda pair of contacts 33 and 34 to be selectively engaged thereby,depending upon the direction of operation of motor 3 and cylinder Idriven thereby. For this purpose the threaded shaft II is shown asprovided with an extension to which a pulley ,35 is keyed or otherwiserigidly secured. Ex-

tending around and frictionally engaged with pulley 35 is a belt 36, theopposite ends of which are rigidly attached to contactor 32 on oppositesides of the point of pivotal support of the latter. Suitable means (notshown) are provided for insuring the desired degree of tension of belt36 against pulley 35. A switch of the general character illustrated at2| is shown and described in detail in Patent No. 1,964,199, grantedJune 26, 1934, to C. T. Evans.

With motor 3 and cylinder I operating in a direction to effect movementof nuts I2 and I3 toward the right the contactor 32 of switch 2| will beengaged with contact 34,-thus providing an energizing circuit for theoperating winding 20 of accelerating switch 20, which circuit extendsfrom line L through limit switch 9, as previously traced, by conductor24 through contact 34 and contactor 32, by conductor 31 through saidwinding 23, by conductor 33 through contacts I and by conductor 3i toline L Contacts 20*, 23, 20 are thus closed to shunt resistances R R Rto provide for accelerated operation of motor 3 and cylinder I. Normallyclosed contacts 20 are opened, but as previously mentioned, theenergizing circuit for winding 1 of switch 1 is adapted to be maintainedthrough contacts 1* of switch 1.

Pending opening of push button switch I6, or opening of tub door 5 withconsequent opening of contacts I1 of door switch I1, motor 3 willoperate under the conditions aforedescribed until nut I3 in its movementtoward the right engages and opens limit switch 3, with consequentde-energization of the windings I! and 20 of reversing switch I andaccelerating switch 20, respectively. Upon opening of limit .switch 9the limit switch 8 is closed with a snap action to establish anenergizing circuit for the winding 8 of reversing switch 6, whichcircuit may be traced from line L through push button switch I 6,contacts I1 of door switch I1, contacts II and I9 respectively, of inchpush button switches l8 and I9, by conductor 23 through limit switch 8,by conductors 39 and 40, through said winding 6*, by conductor-43through the normally closed contacts 20 and by conductor 3| to line LContacts 6 6, 6 are thus closed to establish power connections throughresistances R R3, R respectively, for motor 3 to provide for pluggingthereof under reduced voltage and torque conditions, whereupon the motorand cylinder I driven thereby are smoothly and gradually slowed to zerospeed. Immediately upon attainment of zero speed motor 3 starts toslowly'drive cylinder l in a direction such as to cause movement of nutsl2 and I3 toward the left. Normally open contacts 6 and 6 are alsoclosed upon response of switch 6,-contacts 6 providing a maintainingcircuit for winding 6? paralleling the interlock contacts 20, andcontacts providing an electrical interlock for winding 26 ofaccelerating switch 20.

At the instant reverse movement of cylinder I is initiated the contactor32 of switch 2| will be tilted by belt 36 intoengagement with contact33, whereupon an energizing circuit for the winding 20- of acceleratingswitch 20 will be established, which .circuit extends from line Lthrough limit switch 3, as previously traced, by conductor 39 throughcontact 33 and contactor 32, by conductor 3] through winding 20, byconductor 38 through contacts'6 and by conductor 3| to line L. Contacts20*, 20, 20 of switch 20 are thus closed to shunt resistances R R", R toprovide for accelerated operation of motor 3 and cylinder l. Normallyclosed, contacts 20 and 20 are opened, but as previously mentioned, theenergizing circuit for winding 6 of switch 6 is adapted to be maintainedthrough contacts 6 of switch 6.

The aforedescribed cycle of operations is repeated automatically untilit is desired to shut down the entire system. Such a shut down may beeifected at will by opening the push button switch IE or by opening thetub door 5 which results in opening the contacts I'l of door switch 11,either of which effects de-energization oi the operating windings of theactive reversing-switch and the accelerating switch 20. Opening ofeither the push button switch I6 or contacts I! also efiectsde-energization of the operating winding 22- 01' brake 22, the circuitfor which may be traced from line L through push button switch l6 andcontacts IT, by conductor 44 through winding 22 to line L. It will beapparent that brake 22 is adapted to be released during forward, reverseor plugging operation of motor 3, and said brake acts to stop theequipment upon deenergization of. the motor.

The control system includes manually operable means to provide forinching operation of motor 3 in opposite directions selectively whilewinding 22 of brake 22 to effect release thereof during inchingoperation of the motor. As hereinbefore described, contacts I! of doorswitch H are adapted to be closed when tub door 5 is opened. Thus withthe push button switch i 6 closed and contacts ii closed depression ofinch push button switch l8 establishes an energizing circuit for theoperating winding 6" of reversing switch 6, which circuit may be tracedfrom line L through push button switch I6, contacts I1 and contacts I8by conductor through inch limit switch 21 and thence by conductors 42and 40 through winding 6 to line L as previously traced. Switch 6responds to effect slow speed operation of motor 3 as hereinbeforedescribed.

On the other hand, depression of inch push button switch l9 establishesan energizing circuit for the operating winding I of reversing switch I,which circuit may be traced from line L through push button switch l6,contacts l'l and contacts I9 by conductor 26 through inch limit switch28 and thence by conductors 29 and 25 through winding I to line L aspreviously traced. Switch I responds to effect slow speed operation ofmotor 3 as hereinbefore described.

Continued depression of either of the inch push button switches l8 andill will result in energization of the operating winding 20 ofaccelerating switch 20,-it being apparent that the contactor 32 ofswitch 2| will be or will have been tilted into engagement with one orthe otherof the contacts 33 or 34 upon initiation of operation of Thecirwinding 20 to line L as previously traced- Switch 20 responds toeffect accelerated operation of motor 3 in one direction or theother,,as hereinbefore described.

As will be readily apparent from the drawingand from the foregoingdescription, the motor will be de-energized and brake 22 will operate tostop the equipment upon release of the depressed inch push button switchl8 or IS.

The inch limit switches 21 and 28 are adapted to shut down the systemupon movement of traveling nuts 12 and [3 into opposite limits,respectively, to provide against movement of said nuts off of threadedshaft l I during inching operations. It will be noted that the number ofrevolutions through which the cylinder 1- is to be operated in oppositedirections during automatic operation of the equipment is determined bythe spacing of nutsl2 and i3 on shaft H, and obviously such spacingwould beinterferedwith if saidnuts were allowed to run off of saidshaft. i V

In certain cases it may be desirabe to inch the cylinder l with lowtorque corresponding to that produced by motor 3 when acceleratingswitch 20 is open. It isobvious to those skilled inthe art that inchpush button switches l8 and I9 may be respectively equipped withan-additional set of normally closed contacts; these contacts to beconnected in series with each other and in series. with the operatingwinding 20, so that accelerating switch 20 is always open duringinching.

What I claim as new and desire to secure by Letters Patent is:

1. In a control system of the character described, in combination, areversible electric motor, a load to be driven thereby in eachdirection, means for completing an energizing circuit for said motorwhereby said load is driven in one direction under substantially normaltorque con; ditions, means including a limit switch operableautomatically to'efiect interruption of said motor circuit, said meansbeing simultaneously operable to effect establishment of an alternativeenergizing circuit adapted to effect plugging of said motor underrelatively low torque conditions, whereby said load is gradually broughtto rest and is thereafter immediately driven in the reverse direction, aswitch comprising a stationary contact and an oscillatable contactor,and means including a drag connection between said load and saidcontactor whereby the latter is engaged with said contact immediatelyupon reversal of the former in the manner aforementioned, said contactorwhen engaged with said contact being adapted to effect completion of anenergizing circuit for said motor whereby the latter is adapted to drivesaid load under substantially normal torque conditions in the directionlast mentioned.

2. In a control system of the character described, in combination, areversible electric motor, a load to be driven thereby in eachdirection, a pair of normally open electromagnetically operabledirectional switches, one of said switches being adapted uponenergization and closure thereof to effect completion of a circuit foroperation of said motor in one direction under relatively low torqueconditions, a normally open electromagnetic accelerating switch operableautomatically thereafter to effect completion of a circuit for operationof said motor in said direction under substantially normal torqueconditions, a limit switch operable upon a given number of revolutionsof said load to effect deenergization and opening of said last mentioneddirectional switch and said accelerating switch, said limit switch beingsimultaneously operable to establish an energizing circuit for the otherof said directional switches to effect completion of a circuit adaptedto effect plugging of said motor under relatively low torque conditions,whereby said load is gradually slowed to rest and is thereafterimmediately driven in the reverse direction, means operable immediatelyupon reversal of said load in the manner aforementioned to establish anenergizing circuit forsaid accelerating switch to effect completion of acircuit for operation of said motor under substantially normal torqueconditions in the direction last mentioned, said last mentioned meansincluding a switch having a pair of stationary contacts and a pivotedcontactor movable into engagement with one or the other of saidcontacts, depending'upon the direction of rotation of said load, saidmeans including a drag connection between said motor and said contactor.

3. In a control system of the character described, in combination, acylindrical container to be rotatably driven in each direction, areversible electric motor having a driving connection with saidcontainer, means for completing an energizing circuit for said motorwhereby said container is rotated in one direction at a relatively highspeed, means including a limit switch operable automatically to effectinterruption of said motor circuit, means including a second limitswitch operable automatically and simultaneously with said firstmentioned limit switch to effect establishment of an alternativeenergizing circuit for said motor to effect plugging thereof underrelatively low torque conditions, whereby said container is graduallyslowed to rest and is thereafter immediately driven in the reversedirection at a relatively slow speed, a switch comprising a stationarycontact and an oscillatable contactor, means including a frictionaldriving connection between said container and said contactor whereby thelatter is engaged with said contact immediately upon reversal of theformer in the manner aforementioned, said contactorwhen engaged withsaid contact being adapted to effect completion of a circuit for saidmotor whereby the latter is adapted to drive said container in thedirection thereof last mentioned at a relatively high speed, said secondmentioned limit switch being operable automatically to interrupt saidlast established motor circuits upon a predetermined number ofrevolutions of said container in the direction last mentioned.

4. In a control system of the character described,'in combination, acylindrical container to be rotatably driven in each direction, areversible electric motor having a driving connection with saidcontainer, means for completing an energizing circuit for said motorwhereby said container is rotated in one direction at substantiallynormal speed, means including a limit switch operable automatically toeffect interruption of said motor circuit, means including a secondlimit switch operable automatically and simultaneously with said firstmentioned limit switch to effect establishment of an alternativeenergizing'circuit for said motor to effect plugging thereof underrelatively low torque conditions, whereby said container is graduallybrought to rest and is thereafter immediately driven in the reversedirection at a relatively slow speed, a switch comprising a stationarycontact and an oscillatable contactor, means including a frictionaldriving connection between said container and said contactcr whereby thelatter is engaged with said contact immediately upon reversal of theformer in the manner aforementioned, said contactor when engaged withsaid contact being adapted to effect completion of a circuit for saidmotor whereby the latter is adapted to drive said container in thedirection last mentioned at substantially normal speed, said secondmentioned limit switch being operable automatically to interrupt saidlast established motor circuits upon apredetermined number ofrevolutions of said container in the direction, last mentioned, andmeans for positively interlocking said limit switches to insure closureof each upon opening of the other of same.

5. In a control system of the character described, in combination, acylindrical container to be rotatably driven in each direction, areversible electric motor having a driving connection with saidcontainer, means for completing an energizing circuit for said motorwhereby said container is rotated in one direction at substantiallynormal speed, means including a limit switch operable automatically toeffect interruption of said motor circuit, means including a secondlimit switch operable automatically and simultaneously with said firstmentioned limit switch to effect establishment of an alternativeenergizing circuit for said motor to effect plugging thereof underrelatively low torque conditions, whereby said container is graduallybrought to rest and is thereafter immediately driven in the reversedirection at a relatively slow speed, a switch comprising a stationarycontact and an oscillatable contactor, means including a frictionaldriving connection between said container and said contactor whereby thelatter is engaged with said contact immediately upon reversal of theformer in the manner aforementioned, said contactor when engaged withsaid contact being adapted to effect completion of a circuit for saidmotor whereby the latter is adapted to drive said container in the2,187,634 direction last mentioned at substantially normal speed, saidsecond mentioned limitswitch being operable automatically to interruptsaid last established motor circuits ,upon a predetermined number ofrevolutions of said container in the direction last mentioned, means forpositively interlocking said limit switches to insure closure of eachupon opening of the other of same, and spring means associated with saidlimit switches to effect movements thereof with a snap action.

\ 6. In a control systemof the character described, in combination, asubstantially cylindrical container rotatable upon a horizontal axis, anelectric motor having a positive driving con- 5 nection with saidcontainer, a pair of normally open electromagnetically operabledirectional switches respectively adapted when closed to provide circuitconnectionsfor forward and reverse operation of said motor underrelatively low torque conditions, means for insuring closure andopening. of the respective switches in sequence to effect periodicplugging and reversal of the direction of operation of said motor, saidmeans comprising a pair of limit switches each having a pivotedcontactorand an associated stationary contact, said 'contactors beingmechanically interlocked to insure against simultaneous engagementthereof with said contacts, a pair of traveling nuts associated withsaid container and operable to sequentially eifect opening of each ofsaid limit switches while simultaneously efiecting closure of the ,otherof same upon like amounts of rotation of said container in oppositedirections respectively, a normally open accelerating switch adaptedwhen closed to provide circuit connections for operation of said motorunder substantially normal torque conditions in either direction,closure of said accelerating switch, being subject to closure of each ofsaid directionalswitches, respectively, andna direction-responsiveswitch common to said limit switches, said direction-responsive switchcomprising a pair of spaced stationary contacts and an oscillatablecontactor associated therewith, 5 a frictional driving connectioninterposed between said container and said contactor whereby the latteris engageable with said stationary contacts alternately as an incidentto reversal of the direction of rotation of said container, the

arrangement being such that immediately upon reversal of said containerfollowing plugging of said motor said direction-responsive switchcontactor eifects engagement with one of its associated contacts whereby,an energizing circuit is "established for said'accelerating switch toprovide for operation of said motor under substantially normal torqueconditions. y

7. In a device ofthe character described, in combination, a reversibleelectric driving motor, a load tobe rotatably driven thereby in eachdirection, a pair of electromagnetically operable reversing switches'rorcontrolling thedirection,

of operation of said motor, means operable upon a predetermined numberof revolutions of said load in each direction, respectively, to efiectsequential energization of said reversing switches to provide forplugging and subsequent reversal of said motor under predeterminedrelatively low voltage conditions, an electromagnetically oper-" ableaccelerating switch. common to said reversing switches, means operableimmediately upon reversal oi said motor toeil'ect energization of saidaccelerating switch to provideior operation of said motor under normalvoltage conditions, said last mentioned means comprising an oscil-,

latable contactor, a pair of contacts to be selec-" tively engagedthereby, and means providing a friction driving connection between saidload and said contactor, whereby the latter is moved alternately fromeach extreme position thereof to the other only upon the reversingoperations of said load.

8. In a device of the character described, in combination, a reversibleelectric driving motor, a load to be rotatably driven thereby in eachdirection, a pair of electromagnetically operable reversing switches forcontrolling the direction of operation of said motor, means operableupon a predetermined number of revolutions of said load in eachdirection respectively to effect sequential energization of saidreversing switches to provide for plugging and subsequent reversal ofsaid motor under predetermined relatively low voltage conditions, meansassociated with said reversing switches and operable automatically inresponse to operation of direction-re sponsive means to provide foroperation of said motor under normal voltage conditions, saiddimotion-responsive means comprising an' oscillatable contactor, a pairof contacts to beselectively engaged thereby, and means to provide adrag connection between said load and said contactor, whereby the latteris moved alternate- 1y from each extreme position thereof to the otheronly upon the reversing operations of said load.

9. In a controller for motor operated washing machines, in combination,a reversible electric driving motor, an element to be rotatably driventhereby in each direction, means operable automatically by said elementupona given amount of rotationthereby in eachdirection to initiateoperation 01 said motor under relatively low torque conditions to efiectplugging thereof and subsequent rotation of said element in the reversedirection at a relatively slow speed, means operable automatically andsubstantially simultaneously with reversal of said element to effectacceleration of the rate of operation of said motor in each direction,said last mentioned means comprising a drag device associated with otherof said reversing switches and said acceler said element and a pluralityof sets of contacts ating switch in sequence to provide for rotation Iof said container in one direction by said motor under normal voltageconditions, means comprising a limit switch operable upon a given numberof revolutions of said container to effect deenergizat ion of saidreversing switch and said accelerating switch with consequentinterruption of the motor circuit, means operable substantiallysimultaneously with said last mentioned means to eilect energization andclosure of the other of said reversing switches to provide for pluggingof said motor under relatively low voltage conditions with consequentgradual stopping and subsequent reversal of the direction of rotation ofsaid container, switching means comprising a contact element movable inopposite directions between given circuit controlling positions, meanscomprising a frictional driving connection between said container andsaid contact element, whereby said contact element is moved from onecircuit controlling position thereof to the other as an incident of thereverse rotation of said container, and means adapted upon such movementof said contact element to automatically efiect energization and closureof said accelerating switch, whereby reverse operation of said drivingmotor under said normal voltage conditions is effected, to therebyinsure completion of the accelerating circuit connections for said motoronly upon initiation of relatively slow rotation of said load in saidreverse direction.

11. In a controller for motor operated washing machines, in combination,a reversible electric driving motor, a substantially cylindrical,container to be rotatably driven thereby in each direction, a pair ofelectromagnetically operable reversing switches adapted when energizedselectively to alternately provide reverse circuit connections for saidmotor, an electromagnetically operable accelerating switch, meansincluding manually operable means for initially eifecting energizationand closure of one or the other of said reversing switches and saidacceleratin switch in sequence to provide for rotation of said containerin one direction by said motor under normal voltage conditions, meanscomprising a limit switch operable upon a given number of revolutions ofsaid container to effect deenergization of said reversing switch andsaid accelerating switch with consequent interruption of the motorcircuit, means operable substantially simultaneously with said lastmentioned means to eifect energization and closure of the other of saidreversing switches to provide for plugging of said motor underrelatively low voltage conditions with consequent gradual stopping andsubsequent reversal of the direction of rotation of said container,switching means comprising a contact element movable in oppositedirections between given circuit controlling positions, means comprisinga frictional driving connection between said container and said contactelement, whereby said contact element is moved from one circuitcontrolling position thereof to the other as an incident of the reverserotation of said container, and means adaptedupon such movement of saidcontact element to automatically effect energization and closure of saidaccelerating switch, whereby reverse operation of said driving motorunder said normal voltage conditions is effected, to thereby insurecompletion of the acceleratin circuit connections for said motor onlyupon initiation of relatively slow rotation of said load in said reversedirection, said limit switch also acting upon said given number ofrevolutions of said container in said-reverse direction to effectdeenergization of the second mentioned reversing switch and saidaccelerating switch with consequent interruption of the motor circuit,said simultaneously operable means being effective to reenergize saidfirst mentioned reversing switch, whereby the operating cycleaforedescribed is repeated.

12. In a controller for motor operated washing machines, in combination,a reversible electric driving motor, a substantially cylindricalcontainer to be rotatably driven thereby in each direction, a pair ofelectromagnetically operable reversing switches adapted when energizedselectively to alternately provide reverse circuit connections for saidmotor, an electromagnetically operable accelerating switch, meansincluding manually operable means for initially eifecting energizationand closure of one or the other of said reversing switches and saidaccelerating switch in sequence to provide for rotation of saidcontainer in one direction by said motor under normal voltageconditions, means comprising a limit switch operable upon a given numberof revolutions of said container to effect deenergization of saidreversing switch and said accelerating switch with consequentinterruption of the motor circuit, means operable substantiallysimultaneously with said last mentioned means to effect energization andclosure of the other of said reversing switches to provide for pluggingoi. said motor under relatively low voltage conditions withconsequentgradual stopping and subsequent reversal of the direction ofrotation of said container, switching means comprising a contact elementmovable in opposite directions between given circuit controllingposition, means comprising a frictional driving connection between saidcontainer and said contact element, whereby said contact element ismoved from one circuit controlling position thereof to the other as anincident of the reverse rotation of said container, and means adaptedupon suchmovement of said contact element to automatically efiectenergization and closure of said accelerating switch, whereby reverseoperation of said driving motor under said normal voltage conditions isefiected, to thereby insure completion of the accelerating circuitconnections for said motor only upon initiation of relatively slowrotation of said load in said reverse direction, said limit switch alsoacting upon said given number of revolutions of said container in saidreverse direction to eifect deenergization of the second mentionedreversing switch and said accelerating switch with consequentinterruption of the motor circuit, said simultaneously operable meansbeing effective to reenergize said first mentioned reversing switch,whereby the operating cycle aforedescribed is repeated, and meansincluding a normally closed manually operable switch adapted uponopening thereof to effect at will a full stop of said motor and thecontainer 0 driven thereby.

13. In a controller for motor operated washing machines, in combination,a reversible electric driving motor, a substantially cylindricalcontainer to be rotatably driven thereby in each direction, a pair of'electromagneticallyoperable reversing switches adapted when energizedselectively to alternately provide reverse circuit connections for saidmotor, an electromagnetically operable accelerating switch, meansincluding manually operable means for initially effecting energizationand closure of one or the other of said reversing switches and saidaccelerating switch in sequence to provide for rotation of saidcontainer in one direction by said motor under normal voltageconditions, means comprising a limit switch operable upon a given numberof revolutions of said container to effect deenergization or saidreversing switch and said accelerating switch with consequentinterruption of the motor circuit, means operable substantiallysimultaneously with said last mentioned means to eflfect energizationTahd closure of the other of said reversing switches to provide forplugging of said motor under relatively low voltage conditions withconsequent gradual stopping and subsequent reversal of the direction ofrotation oi. said container, switching means comprising a contactelement movable in opposite directions between given circuit controllingpositions, means comprising a frictional driving connection between saidcontainer'and said contact element, whereby said contact element ismoved from one circuit controlling position thereof to the other as anincident of the reverse rotation of said container,

and means adapted upon such movement of said contact element toautomatically effect energize.- tion and closure of said acceleratingswitch, whereby reverse operation of said driving motor under saidnormal voltage conditions is effected, to thereby insure completion ofthe accelerating circuit connections for said motor only upon initiationof relatively slow rotation of said load in said reverse direction, saidlimit switch also acting upon said given number of revolutions of saidcontainer in said reverse direction to effect deengization of the secondmentioned reversing switch and said accelerating switch with consequentinterruption of the motor circuit, said simultaneously operable meansbeing eifective to reenergize said first mentioned reversing switch,whereby the operating cycle aforedescribed is repeated, and meansincluding a normally closed manually operable switch adapted upon openinthereof to effect at will a full stop of said motor and the containerdriven thereby, and means associated with said last mentionedmeans toeffect operation of said motor in one direction or the other at will.

able to subsequently initiate operation of said motor in the reversedirection at a relatively slow speed, means operable automatically toinsure full power electrical connection of said motor to effectacceleration of the rate of operation thereof to substantially normalspeed only upon reversal thereof, said last mentioned means comprising adrag device associated with said element, and a plurality of sets ofcontacts respectively controlled by said drag device in accordance withthe direction of rotation of said element.

RALPH G. LOCKETT.

